Highly refractive, scratchproof tio2 coatings in mono- and multilayers

Abstract

The invention relates to coated products containing a substrate (S) provided with a coating consisting of a single high refractive index and scratch-resistant layer (A) or provided with a multilayer structure in which layers (A) alternate with lower refractive index layers (B), wherein the layers (A) are characterised in that they contain particularly finely divided TiO 2 nanoparticles.

1 .- 14 . (canceled) 
     
     
         15 . A coated product comprising a substrate (S), of an organic polymer, and at least one coating comprising at least one layer (A), which comprises finely divided TiO 2  nanoparticles in an amount of from 58 to 95 wt.%, based on the coating (A). 
     
     
         16 . The coated product according to  claim 15 , comprising from 80 to 90 wt.% of the TiO 2  nanoparticles, based on the coating (A). 
     
     
         17 . The coated product according to  claim 15 , wherein the at least one layer (A) has a layer thickness of greater than 120 nm. 
     
     
         18 . The coated product according to  claim 15 , wherein the at least one layer contains no further nanoparticles apart from the TiO 2  nanoparticles. 
     
     
         19 . The coated product according to  claim 15 , wherein at a wavelength of 405 nm, the at least one layer (A) has a value for the sum of light absorption and scatter of less than or equal to 10%. 
     
     
         20 . An optical data storage medium obtained from the coated product according to  claim 15 . 
     
     
         21 . The coated product according to  claim 15 , wherein the at least one layer (A) is obtained from a coating composition comprising
 i. an anhydrous suspension of TiO 2  nanoparticles having a d 100  value of less than or equal to about 100 nm in an organic solvent having a boiling point greater than or equal to 100° C.,   ii. a binder,   iii. a photo- or thermo-initiator,   iv. optionally additives, and   v. an organic solvent   
     
     
         22 . The coated product according to  claim 15 , wherein the product has the layer sequence (S)—(A) or (A)— (S)—(A), measured in a wavelength range of from 380 to 420 nm. 
     
     
         23 . The coated product according to  claim 15 , wherein at least one coating additionally comprises at least one further layer (B) which has a refractive index n less than or equal to 1.65, measured in a wavelength range of from 380 to 420 nm. 
     
     
         24 . The coated product according to  claim 15 , wherein the substrate (S) comprises an organic polymer selected from the group consisting of polycarbonate, poly(methyl) methacrylate, polyester and cycloolefin polymer. 
     
     
         25 . The coated product according to  claim 22 , wherein the binder is selected from the group consisting of polyfunctional acrylates. 
     
     
         26 . A process for the production of the coated product according to  claim 15  containing a layer (A), comprising the steps for application of a layer (A)
 i. coating a substrate (S), of an organic polymer, with a pouring solution comprising the components
 a. an anhydrous suspension of TiO 2  nanoparticles having a d 100  value of less than or equal to about 100 nm in an organic solvent having a boiling point greater than or equal to 100° C., 
 b. a binder, 
 c. a photo- or thermo-initiator, 
 d. optionally additives, and 
 e. an organic solvent; 
 
 ii. removing excess pouring solution, 
 iii. removing the organic solvent, and 
 iv. crosslinking the coating. 
 
     
     
         27 . A coating composition for the coating of a substrate (S), of organic polymers comprising
 i. an anhydrous suspension of TiO 2  nanoparticles having a d 100  value of less than or equal to about 100 nm in an organic solvent having a boiling point greater than or equal to 100° C.,   ii. a binder,   iii. a photo- or thermo-initiator,   iv. optionally additives, and   v. an organic solvent.   
     
     
         28 . The coated product according to  claim 15 , wherein the coated product does not contain an antireflection layer.